The total synthesis of (plus or minus)-delta 9- and delta 8-6a,10a-cis-cannabidiols (CBD) was achieved (J. Org. Chem., 42, 2563 (1977)). The acid-catalyzed (p-TSA) transformation products of cis-CBD's were isolated and identified as the ring closed cis-cannabinoids. The first total synthesis of racemic and optically active delta 9- and delta 8-cis-THC's was described (Tetrahedron 33, 2055 (1977)) from carene oxide, utilizing the stereo-specific intramolecular epoxide cleavage by phenolate anion. The scope of this reaction is being further explored. A novel cannabinoid containing a 1,8-cineol moiety was synthesized (Experientia, 33, 577 (1977)). As a result of SAR study in cannabinoids it was found that abnormal cannabidiol was devoid of overt behavioral effects in dogs but produced marked hypotension with only slight bradycardia in anesthesized dogs at 0.5 mg/kg (iv) (Experientia, 33, 1204 (1977)). 8,9-Epoxy-hexahydrocannabinol (EHHC) was shown to have immunosuppressive effects in mice (J. Pharm. Exper. Ther., 201, 573 (1977)). We have recently reported a practical one-step synthesis of delta 9-THC (J. Am. Chem. Soc., 96, 5860 (1974)). The potential of this process is being explored for the preparation of other delta 9-THC derivatives, metabolites, etc.